Spain's biggest bank Santander on Thursday said it owned around 30 billion euros of Spanish sovereign debt at the end of September.

"When it comes to public debt, exposure to Spanish sovereign debt is around 30 billion euros," Santander Chief Executive Alfredo Saenz said during a conference call with analysts.

He added the holdings had come down from 35 billion euros in the previous quarter after debt matured.

Saenz also said bad loans would peak across the group towards the end of 2013.

(Reporting by Sonya Dowsett and Blanca Rodriguez, writing by Julien Toyer, editing by Fiona Ortiz)